On 15 March 2000, another ambiguous asteroid alert was issued on
the
internet. Since then, the announcement has been posted on
numerous
mailing lists and news websites (see Daniel Fischers news
report
further below). This time, however, the alert was announced by
members
of the media, not by the astronomical community. In a somewhat
equivocal "Minor Planet Astro Alert", posted to
subscribers of their
asteroid mailing list (asteroid@skypub.com),
the U.S. American
astronomy journal Sky & Telescope, claimed that the newly
discovered
asteroid 2000 EW70 "could threaten Earth at some future
date."

While this vague formulation is rather speculative, given its
lack of
any specific data, there is no evidence, to my knowledge, to
suggest
that asteroid 2000 EW70 poses any threat to collide with Earth in
the
near future. Asked whether he could comment on 2000 EW70, Brian
Marsden
has confirmed that he is "not aware of any computations
showing that
any impact is remotely possible during the next several
decades" (see
his remarks further below).

Speaking from my own experience, science writers, web authors and
net
moderators are well advised to consult with the experts in the
field
before publishing misguided or alarmist asteroid alerts. Mind
you, this
advice is perhaps even more valid for some rash NEO researchers
who
have been prone to issue rushed impact warnings, often quite
unnecessarily.

Extraterrestrial gases, including helium, are trapped in
"buckyball"
molecules in a layer of sedimentary clay found in many places on
Earth, according to a paper to be published March 28, 2000, in
the
Proceedings of the National Academy of Sciences.

The discovery provides a new tool for tracing asteroid and comet
impacts in Earth's geological and biological records. A
University
of Hawaii geochemist and her colleagues, including a NASA
scientist,
found gases that did not originate on Earth inside buckyballs, or
fullerene carbon molecules.

The fullerene molecule is a hollow, cage-like structure typically
made of 60 or more carbon atoms; it is also referred to as a
"buckyball," in honor of Buckminster Fuller, designer
of the geodesic
dome that resembles the molecule.

"We discovered extraterrestrial noble gases trapped inside
buckyballs
in a one-inch thick sedimentary layer of clay that is exposed at
several locations on Earth," said Ted Bunch, a scientist at
NASA's
Ames Research Center in California's Silicon Valley. "The
buckyballs
containing the gases arrived on Earth about 65 million years ago
during an asteroid impact that scientists theorize ended the age
of
the dinosaurs. The clay layer that formed from fallout of the
impact
debris was globally distributed," Bunch explained.

Luann Becker, of the University of Hawaii, Honolulu, HI; Robert
Poreda, of the University of Rochester, Rochester, NY; and Ted
Bunch
of NASA Ames, discovered the extraterrestrial gases in the
fullerenes. An advance copy of the article will be posted
on the
Internet on March 21 at http://www.pnas.org

"Helium from different sources on Earth, like our atmosphere
or the
emissions from volcanoes, have a very different isotopic
signature
from the helium in a meteorite," Becker said. An
isotopic signature
is the ratio of the isotopes of an element; for example,
terrestrial
helium consists of a small amount of helium 3 (whose nucleus has
two
protons and one neutron), and mostly helium 4 that has 2 protons
and
2 neutrons. Cosmic helium is mostly helium 3.

"The helium we found within the fullerene cages of
Australia's
Murchison meteorite, for example, is similar to the helium that
existed when our Solar System first formed," Becker stated.
That
finding points to a cosmic source for the fullerenes, the
researchers
say. In contrast, molecules formed in the high pressure and
temperature of an earthly impact or the heat of wildfires that
followed would have encapsulated terrestrial helium, according to
the
researchers.

They say the finding also supports the theory that atmospheric
gases
and organic compounds arrived on the Earth's surface during
asteroid
and comet strikes early in the planet's history when impacts were
very numerous. The discovery relates to previous work by Becker
and
Bunch, published in Nature in July 1999 that first identified
naturally occurring fullerenes in a meteorite. The scientists
found
significant quantities of very large fullerene molecules, some
containing as many as 400 carbon atoms, in samples from the
4.6-billion-year-old Allende meteorite that landed in Mexico
three
decades ago.

The subsequent work examined several Cretaceous/Tertiary boundary
clay sediments distributed worldwide, including deposits in
Denmark,
New Zealand and North America. In each case, the researchers
found
fullerenes that encapsulated noble gases with unmistakable
extraterrestrial and possibly extra-solar isotopic signatures.

The scientists examined the one-inch clay layer because it is a
well-studied sediment that contains extraterrestrial iridium and
highly shocked minerals resulting from an asteroid impact 65
million
years ago. A highly shocked mineral is one that has experienced
temperatures of more than 2,000 C and pressures of about 400,000
atmospheres from impact shock. The clay layer documents a period
of
abrupt change in biological evolution, including mass extinction
of
the dinosaurs, now generally attributed to the impact of a
carbonaceous asteroid with the Earth.

Becker said she hopes to expand the research to examine other
periods
of mass extinction such as the even more devastating event that
formed the 250-million-year-old Permian/Triassic layer of
sediment.
She added that she hopes to determine if impacts with Earth
trigger
global change, including whether fullerenes of extraterrestrial
origin delivered gases and carbon necessary to establish life on
Earth.

"We now have a powerful new tracer to look at sediment
layers very
carefully," Becker said. "It opens new possibilities in
looking at
the problem of how planetary atmospheres evolved and maybe even
how
life evolved on Earth and perhaps on other moons and
planets." She
said she also hopes to work with astronomers to study the
formation
of fullerenes. "We have yet to learn why these things are
there and
what they tell us about carbon in the universe. We need to figure
out
how to establish their existence and how to search for it."
Grants from the NASA Cosmochemistry and Exobiology programs
supported
the research.

============
(3) 'FOSSIL EVIDENCE' IN MARTIAN METEORITE DUE TO CONTAMINATION

"Jerry Palmer and I happen to have just attended a Von
Karmann
lecture at JPL last night, a panel discussion on the Mars
program.
Dan McCleese (the Mars Program Scientist at JPL) was on the
panel.
He said that, last month, a leader of the team that in 1996
reported
evidence for fossil life in martian meteorite ALH84001 stated
that it
is now clear that terrestrial contamination is the explanation.
Thus
it appears that the case on ALH84001 is pretty nearly closed.
Even
so, educated opinion about the prospects for eventually finding
some
life, past or present, on Mars, ranges all over the map -- it's a
wide open question."

On March 11, 2000, this image of Eros' north polar region was
acquired
by the imager on the NEAR Shoemaker spacecraft, from a range of
206
kilometers (127 miles). The area shown in the image is 10
kilometers
(6.2 miles) across. Most of the north polar region is heavily
cratered
but the region to the left (part of the "saddle") has a
lower crater
density, indicating that the surface has been modified since it
first
formed. Eros' rotational axis lies nearly parallel to its orbital
plane, much as with the planet Uranus, giving the asteroid
exaggerated
"seasons." Now, it is northern summer and the north
pole is in
continuous sunlight. The Sun will set there this June, at Eros'
equivalent of Earth's autumnal equinox. At that time, Eros' south
pole
will begin 12 months of continuous illumination while the north
pole
remains in darkness.
--------------------------------------------------------
Built and managed by The Johns Hopkins University Applied Physics
Laboratory, Laurel, Maryland, NEAR was the first spacecraft
launched in
NASA's Discovery Program of low-cost, small-scale planetary
missions.
See the NEAR web page at http://near.jhuapl.edu
for more details.

The Whipple formula for the emission velocity of meteoroid dust
from:
the surface of a cometary nucleus is reviewed and it is concluded
that,
in normal circumstances, the dust velocity is 'low', typically
being
less than 20% the radial gas velocity. If, however, the dust
particle
contains some embedded snows when it leaves the cometary nucleus,
its
final velocity is considerably increased. (C) 1999 Elsevier
Science
Ltd. All rights reserved.

We present results of our photometric observations of the Apollo
asteroid (4197) 1982 TA and the Mars-crosser 1997 LY4. Their
synodic
rotation periods (3.53802 +/- 0.00005) and (46.07 +/- 0.02) h,
respectively, have been derived. The fast rotation of (4197)
suggests a
lower limit of the bulk density of 1.1 g/cm(3). The mean diameter
of
(4197) is likely in the range 3-6 km, The present knowledge does
not
support a possibility that (4197) is an extinct cometary nucleus
as
suggested from its orbit. The smaller (1.4-3 km), slowly-rotating
asteroid 1997 LY4 is an elongated object with the equatorial axis
ratio
greater than or equal to 1.8. (C) 1999 Elsevier Science Ltd. All
rights
reserved.

the moderately close approach of asteroid 2000 EW70 to Earth this
week could be used for raising the awareness of these kinds of
objects and that they really exist and not just in the movies.
With a
maximum brightness like Pluto EW70 will remain something for
serious
amateur astronomers, but its maximum angular speed of one second
of
arc per one second of time combined with a good northern
declination
makes me wonder: Couldn't one image this object moving over the
sky
in real-time (i.e. at video rate, with 25 or 30 frames a second)
and
make this feed available for television (or at least do a
webcast)?
With a larger amateur (let alone university) telescope and image
intensifier tube and a small video camera it could be done, or
with
an astronomical CCD camera that permits fast readout a few times
a
second. Orbital elements and ephemeris are in the MPEC 2000-E57
of
March 13:http://cfa-www.harvard.edu/mpec/K00/K00E57.html
(there are no new elements).

On March 9, 2000, the 1-meter LINEAR patrol camera in New
Mexico picked up a fast-moving asteroid that could
threaten
Earth at some future date: 2000 EW70 had magnitude 17.5
when
first detected, but the asteroid should brighten 20-fold
next week
as it makes a moderately close flyby, passing only 0.013
Astronomical Units from Earth on March 22nd. 2000 EW70
will
then be at about 11h 30m RA and +25 deg. declination near
the
UMa/Leo border. Small CCD-equipped telescopes can capture
trailed images of 2000 EW70 during this period. Any
telescope
that shows Pluto visually, like 10-inch aperture or
larger, should
show this object - around closest approach, its unusually
rapid
motion (about 1 degree per hour!) should be perceptible in
a
high-power eyepiece." (The original source was an
S&T alert mail.)

My main comment is that there have been *several* orbit updates
of 2000
EW70 since MPEC 2000-E57 on March 13, the most recent being on
MPEC
2000-F15 on March 20. These follow-up MPECs each contain new
orbits for
many hundreds of minor planets, so the newer results for 2000
EW70,
together with observations through March 19, are not set out with
the
prominence of MPEC 2000-E57. The changes are actually quite
modest,
but the new data, plus in particular any that may be obtained
during
the next week or so (after which further observations will not be
possible), will be very useful for examining the circumstances of
future approaches to the earth. I am not aware of any
computations
showing that any impact is remotely possible during the next
several
decades.

Interested to see the bit about Holmes today. It is also quoted
in
the official citation for asteroid Holmes, which I wrote. I don't
remember exactly what it says, but I dare say an internet expert
can
pull it out of the web at the stroke of a key.

Re "Sherlock Holmes & the Solar System", Holmes was
no astronomical
ignoramus or if he was in 1878 when he first met Watson he took
pains
to correct the lapse. At the time of the case of the Greek
Interpreter
he was able to discuss some of the finer points of celestial
mechanics.
"It was after tea on a summer evening, and the conversation,
which had
roamed in a desultory spasmodic fashion from golf clubs to the
causes
of the change in the obliquity of the ecliptic ...
".

You printed an abstract of a LA times article of a study that
concluded
that Global Warming is not necessarily a threat, and might even
save
some people from freezing to death.

My immediate reaction is that freezing to death is not all that
large
as a cause of death. I suspect that a greater benefit would be a
longer
growing season to alleviate hunger in cool climates like Russia,
Mongolia, and Manchuria and improve agricultural success in
places
where modernity has mostly alleviated hunger such as Britain,
Scandinavia, and Canada.

Sunspot pattern 'played a part in sinking of Titanic'
By David Derbyshire, Science Correspondent

A COMBINATION of unusual solar activity and bad timing helped
sink
the Titanic, a new study of sunspots suggests.

Research by Edward Lawrence, a scientist at the Meteorological
Office
for more than 30 years, suggests that the liner set sail across
the
North Atlantic at the riskiest possible time for iceberg
collisions.
The paper, published in the Royal Meteorological Society journal
Weather, also reports that a sudden drop in temperature recorded
by
the crew hours before the collision was a sign that icebergs were
nearby.

Although the politics, personalities and procedures surrounding
the
sinking of the Titanic in the early hours of April 15, 1912, with
the
loss of 1,500 lives, have been documented in detail, Mr Lawrence
believes that the role of the weather has been neglected. Mr
Lawrence, 87 of Bracknell, Berks, said: "Everyone thought
that the
weather was so lovely that it couldn't have had anything to do
with it. But it was a weather phenomenon."

His study of records suggests a strong connection between the
number
of icebergs in the area where the Titanic sank and the 11-year
cycle
of rising and falling sunspots -- dark patches that spasmodically
appear on the surface of the sun. The Little Ice Age of the late
17th
century coincided with a period of extremely low sunspot
activity.

Mr Lawrence also found that one or two years before a sunspot
minimum, stronger than normal anti-cyclones tend to form above
the
north-west North Atlantic. These are associated with light
westerly
winds, more northerlies than usual and colder sea temperatures.
As a
result, icebergs are more commonly found at the southern extreme
of
their range in the North Atlantic in these years.

The maiden voyage of the Titantic in 1912 came just over a year
before the sunspot cycle reached its minimum in July 1913. At
this
time, there were more icebergs than usual, and the ocean was
colder
than normal, said Mr Lawrence. April is also the start of the
spring
peak for icebergs.

----------------------------------------
THE CAMBRIDGE-CONFERENCE NETWORK (CCNet)
----------------------------------------
The CCNet is a scholarly electronic network. To
subscribe/unsubscribe,
please contact the moderator Benny J Peiser <b.j.peiser@livjm.ac.uk>.
Information circulated on this network is for scholarly and
educational use only. The attached information may not be copied
or
reproduced for any other purposes without prior permission of the
copyright holders. The fully indexed archive of the CCNet, from
February 1997 on, can be found at http://abob.libs.uga.edu/bobk/cccmenu.html